This could be considered an age where a premium could be placed on developing economical and commercially feasible alternative fuels such as biodiesel. Biodiesel may be typically a mixture of long chain alkyl (i.e., methyl, propyl or ethyl) esters generally having qualities similar to petroleum-derived diesel fuel and could be used in powering unmodified diesel engines. Biodiesel, hence it name, is derived from the chemical treatment (e.g., transesterification) of renewable non-petroleum based organic materials (e.g., oils made from vegetable oils, animal fats, crushings of certain seed types, and the like). In one possible version of biodiesel, the biodiesel could be made as a result of a transesterification of triglyceride oil supplied by a bio-renewable source (e.g., rape seed crushings).
One possible system and methodology for batch production of biodiesel could have a first stage wherein raw, renewable, organic material could be processed into useable feed stock oil. This stage could include a seed crushing capability and a follow-on oil extractor/filter capacity to produce feedstock oil. This stage could further include the ability to treat and reduce the presence of undesired free fatty acids found in the newly created feedstock oil. This ability could convert the undesired free fatty acids into soap and then remove the soap from the biodiesel manufacturing process. Alternatively, the methodology could use an acidic catalyst to covert the free fatty acids into the esterified free fatty acids that can be consumed in the latter stages of process.
The next stage could have the resultant feedstock oil fed through an insulated tank having a heating unit wherein the feedstock oil could be generally held and heated to a prescribed temperature (e.g., approximately 120° C.). The heating process boils off most of the water present in the feedstock oil. If water is left in the feedstock oil as the oil is further processed, the water present could result in a saponification (soap formation) that inhibits the transesterification reaction.
At the next stage, the heated and purified feedstock oil may then be placed into a transesterification chamber or reactor where the transesterification process [e.g., the triglyceride of the feedstock oil reacts with alcohol (i.e., ethanol) in the presence of the catalyst potassium or sodium methylate] occurs. The alcohol reacts with the fatty acids to form the mono-alkyl esters (e.g., biodiesel) and crude glycerine (a/k/a glycerin, glycerol). The use of significant amounts of alcohol further aids to drive the overall reaction (which is reversible) between the feed stock and the alcohol to completion. Once the reaction is driven to completion, it may form a liquid mixture or solution of heavy phase glycerine and light phase biodiesel/alcohol mixture.
At the next stage, the glycerine-biodiesel mixture could then be transferred to separation module, which in one version could be one or more settling or holding tanks Once the mixture is placed in the tanks, the mixture normally substantially separates (by gravity) into two phases or fractions (e.g., a heavy fraction and a light fraction) over a period of time with, expectedly, the ‘heavy’ fraction of glycerine forming the bottom portion while the ‘light’ fraction of biodiesel forms the top portion of the mixture. Once this separation generally has taken place, the lighter fraction biodiesel can be siphoned off the top of the solution while the heaver fraction glycerine can be pumped out from the bottom of the tank.
Another means to separate out the two fractions efficiently and in relatively high purity may be through the employment of powerful and large capacity centrifuges that generally separate the two components in a much quicker fashion than the tank means. These centrifuges may need to be specifically constructed to prevent sparking/electrostatic discharge and otherwise handle/vent explosive gases from volatile liquids (e.g. methanol) that could occur during separation process.
After separation, the resultant biodiesel fraction could be further purified through the final stage by passed it through a heating module (another heating tank) to remove any residual methanol. The biodiesel can then be passed to a purification module to remove any remaining catalyst and resultant soaps that may still have formed. The purification module in one instance can employ a resin ion exchange column to remove any remaining catalyst and residual soaps. At this point, the collected biodiesel has generally reached of level of refinement that substantially allows it to meet the necessary commercial standards for sale and distribution of biodiesel in the market place.
One of the limitations of this biodiesel manufacturing process and system can be seen in the separation process/module, which generally requires a means of separation that are non-continuous (e.g., settling/holding tanks and/or centrifuges). The use of the settling tank system may require a setup having a large footprint (with resultant relatively high construction, operation, and housing costs) to accommodate several tanks need to handle several mixtures of various batches for ongoing biodiesel production. Conversely, if the system only has limited tank capacity, then biodiesel production may have to be halted until separation has occurred in the tank(s) and fractions have been drained off to allow the tank(s) to receive a new biodiesel-glycerine mixture batch.
When the separation process relies on the use of centrifuges, these centrifuges tend to be generally large in size and especially built to handle the separation of alcohol which can be very dangerous (e.g., explosive) if not properly handled (e.g., vented). Such machines could be very expensive (e.g., to obtain and operate) and as a result could make the biodiesel manufacturing process commercially unfeasible.
What is needed there for is a simple, cost-effective, continuous flow separator and respective process of use for same that provides a significantly high fraction purity yield separation of glycerine from the biodiesel, while utilizing a small footprint and generally requiring one unit per processing unit.